1. Field of the Invention
The present invention relates to a method of manufacturing a display device. More specifically, the present invention relates to a method of manufacturing a liquid crystal display device or an organic EL display device that prevents brightness unevenness related to printing unevenness of orientation film or prevents display unevenness due to inkjet coating unevenness of organic film.
2. Description of the Related Art
A liquid crystal display panel used for the liquid crystal display device includes a TFT substrate and a counter substrate that faces the TFT substrate. Pixels having, for instance, a pixel electrode and a thin-film transistor (TFT) are formed in a matrix pattern on the TFT substrate. A color filter, for example, is formed on the counter substrate and disposed at a place corresponding to the pixel electrode on the TFT substrate. Liquid crystal is sandwiched between the TFT substrate and the counter substrate. An image is formed by exercising pixel-specific control over the light transmittance of liquid crystal molecules.
In the liquid crystal display device, the orientation film formed by the TFT substrate and the counter substrate provides initial orientation of the liquid crystal molecules. A video signal is applied to the pixel electrode so that an electric field formed between the pixel electrode and a counter electrode changes the status of the initial orientation of the liquid crystal molecules, thereby controlling the amount of light transmitted through the liquid crystal display panel. The initial orientation of the liquid crystal molecules is defined by rubbing the orientation film.
The orientation film is obtained, for instance, by applying a liquid organic material having a predetermined viscosity to the TFT substrate or the counter substrate by performing offset printing, and then imidizing an orientation film material by baking it. Orientation film offset printing is accomplished by dripping the orientation film material onto a cylindrical anilox roll from an injection nozzle, uniformly applying the orientation film material to the anilox roll with liquid spread means (a doctor blade), transferring the applied orientation film material to a printing plate, and printing the TFT substrate or the counter substrate from the printing plate.
A technology described in JP-A-2007-69382 prevents thickness unevenness of orientation film by uniformly applying the orientation film material to the anilox roll with two doctor blades.